Steam Generation Terminology — Evaporation per Kilogram of Fuel The quantity of water evaporated (in kg) per kilogram of fuel burned in a boiler is commonly called what?

Introduction / Context:
Multiple performance terms exist in boiler engineering, and they are easy to mix up. A very common plant figure is the number of kilograms of steam generated per kilogram of fuel fired. Correctly naming this ratio is important for fuel budgeting and benchmarking performance.

Given Data / Assumptions:

• The metric sought is expressed as kg steam per kg fuel.
• Standard textbook definitions apply.
• No correction to a common reference unless explicitly stated.

Concept / Approach:
The correct term for kg steam per kg fuel is the evaporation ratio (also known as the steam–fuel ratio). It indicates how much steam is produced for each unit mass of fuel, under actual operating conditions. By contrast, “evaporative capacity” usually refers to the rate of steam generation (e.g., kg/h). “Equivalent evaporation from and at 100°C” is a standardised measure that converts actual duty to an equivalent at 100°C, not simply the raw ratio. “Boiler efficiency” is a percentage comparing useful heat in steam to chemical heat input and is not expressed as kg/kg.

Step-by-Step Solution:
Identify desired metric: kg steam per kg fuel.Recall correct term: evaporation ratio (steam–fuel ratio).Check options: none list “evaporation ratio”.Therefore, the correct choice among given options is “none of these”.

Verification / Alternative check:
Plant reports often display both evaporation ratio and equivalent evaporation; they are related but not identical.

Why Other Options Are Wrong:
evaporative capacity: denotes production rate (kg/h), not kg/kg.equivalent evaporation: requires dividing by 2257 kJ/kg reference; not the raw ratio.boiler efficiency: a percentage or fraction based on energy, not mass ratio.

Common Pitfalls:
Using “equivalent evaporation” as a synonym for evaporation ratio; they are distinct concepts.

Final Answer:
none of these